The Small Hive Beetle a Serious New Threat to European Apiculture

The Small Hive Beetle A serious new threat to European apiculture About this leaflet This leaflet describes the Small Hive Beetle (Aethina tumida), a potential new threat to UK beekeeping. This beetle, indigenous to Africa, has recently spread to the USA and Australia where it has proved to be a devastating pest of European honey bees. There is a serious risk of its accidental introduction into the UK. Introduction: the small hive beetle problem The Small Hive Beetle, Aethina tumida It is not known how the beetle reached either (Murray) (commonly referred to as the 'SHB'), the USA or Australia, although in the USA is a major threat to the long-term shipping is considered the most likely route. sustainability and economic prosperity of UK By the time the beetle was detected in both beekeeping and, as a consequence, to countries it was already well established. agriculture and the environment through disruption to pollination services, the value of The potential implications for European which is estimated at up to £200 million apiculture are enormous, as we must now annually. assume that the SHB could spread to Europe and that it is likely to prove as harmful here The beetle is indigenous to Africa, where it is as in Australia and the USA. considered a minor pest of honey bees, and until recently was thought to be restricted to that continent. However, in 1998 it was Could the SHB reach the UK? detected in Florida and it is now widespread Yes it could. There is a serious risk that the in the USA. It is called the small hive beetle SHB could be transported and introduced into to distinguish it from other minor pests of bee the UK, for instance: hives in Africa, known as large hive beetles. within imported honey bees (particularly package* bees and complete colonies) At the time of writing, the SHB is not in swarms of bees or feral colonies thought to be present in the UK. inadvertently carried on container shipping or airfreight The beetle can multiply to huge numbers in used beekeeping equipment, comb and within infested colonies where it eats brood, beeswax destroys combs and if uncontrolled ultimately on imported goods such as fruit destroys them. in soil material, for instance with imported plants or carried on heavy machinery The resulting economic impact on the beekeeping industry in the USA has been (*A bee package is a queen plus 10,000 severe. Within two years of its discovery, at worker bees despatched in a sealed screened least 20,000 colonies were destroyed by the container) beetle, costing many millions of dollars. It has also been found in Manitoba, Canada where it arrived with beeswax imported from the USA. In October 2002, it was found in New South Wales and Queensland, Australia. The economic consequences to the beekeeping industry in Australia are likely to be extremely serious, jeopardising bee exports, pollination services and honey production. 2 Small hive beetle biology The small hive beetle belongs to a family of scavenger beetles known as the Nitidulidae. Many of them are pests of fruit and stored food, and some like the SHB have a close association with social hymenoptera (bees, wasps and ants). Adult beetle anatomy Adult beetles are oval in shape, 5-7 mm long and 3-4.5 mm wide. Immediately after emergence they are coloured reddish-brown, but darken to dark brown or black when fully mature. There is some variation in size but they are about one- third the size of a worker Fig 3. Black adult SHB clearly visible on hive bee. They have club shaped antennae, their frame. They can also be found hiding in bodies are broad and flattened dorso- empty cells at the margins of the brood nest ventrally, their wing cases (elytra) are covered with fine hairs and are short so that a few Egg laying and Alternative Diets segments of the abdomen are visible. Adult beetles are attracted to bee colonies. Once inside, adult beetles lay eggs in irregular masses in hive crevices or brood combs. The eggs are white and about 1.5 x 0.25 mm. Beetles can, however, survive and also lay eggs on a range of fruit, particularly melons. However, it is not known if beetles regularly eat fruit as an alternative food source, or whether this is important for their spread. Fig 1. View of beetle’s head and club shaped antennae Adult beetles are able to survive for up to 2 weeks without food or water. On used brood combs they are able to survive up to 50 days. Larval development After 2-6 days SHB eggs hatch, and the young beetle larvae begin to feed. SHB larvae have characteristic rows of spines on the back and 3 pairs of tiny prolegs near the head (which distinguishes them from wax moth larvae). After 10-14 days, the larvae Fig 2. View of beetle’s abdomen showing have completed their growth and measure shortened wing case (elytra) 10-11 mm in length. 3 Emergence of adults Adult beetles first emerge on average 3-4 weeks later. About one week after emergence adult beetles search for colonies in which to lay eggs. They disperse rapidly over large distances (perhaps 5-10 miles). CSL small hive beetle surveillance The SHB is not thought to be present in the UK. However, from 2003, CSL bee inspectors are increasing statutory surveillance programmes to monitor for SHB presence. The NBU will use Geographical Information Systems (GIS) to prioritise this programme and target apiaries identified as "At risk". For instance, apiaries situated: in warmer parts of the country on sandy soils (suitable for SHB Fig 4. Views of small hive beetle larvae development) showing three pairs of prolegs and distinctive close to civilian and military airports rows of spines, with two large spines close to freight depots and ports of entry - protruding from the rear for instance for fruit and other foodstuffs close to other apiaries containing Reproductive potential imported bees from countries where the Small hive beetles have a huge reproductive SHB is known to be present potential. Individual female beetles are capable of producing up to a thousand eggs during their 4-6 month life. Pupation The next phase of the SHB's lifecycle takes place in the soil. Mature larvae will often mass on the hive bottom board and in corners of frames before moving outside. If feeding and developing on fruit, once mature they will attempt to crawl away looking for soil. Fig 5. Use of GIS to identify apiaries at potential risk 4 Small hive beetle facts Latin Name Aethina tumida (Murray). Common name The Small Hive Beetle (often abbreviated to "SHB"). Host Mainly lives and breeds on its primary host the honey bee - in colonies, stored comb and beekeeping equipment, but it can also survive and reproduce on certain types of fruit, particularly melons. SHB lifecycle Adult beetles lay large numbers of eggs in the hive. Beetle larvae eat brood, pollen and honey. Larvae crawl out of the hive to pupate. Pupation usually occurs in soil outside the hive. Preference for warm sandy soils. Adults can fly at least 5 miles to infest new colonies. Current distribution Indigenous to Africa. First found in United States (Florida) in 1998. Now widespread in the USA. First found in Australia (Queensland, New South Wales) in 2002. Well established. Detected in Canada (Manitoba) in 2002. Not yet established. UK status Exotic pest not currently considered present in the UK. Quarantine pest status with surveillance programmes in place. Methods of spread Spread by movement of package bees, honey bee colonies, swarms, honeycomb, beeswax, soil, and fruit. Adults can survive for two weeks without food and water, 50 days on used comb and several months on fruit. Damage caused to In Africa it is a minor pest to beekeeping as native African beekeeping bees have natural defences. For European honey bees in America and Australia (and therefore almost certainly the UK) the SHB is an extremely serious problem. The beetles multiply to huge numbers, their larvae tunnel through comb to eat brood, ruin stored honey, and ultimately destroy infested colonies or cause them to abscond. Control methods The SHB cannot be eradicated once well established. In the used overseas USA, beekeepers control SHB by using pesticides within the hive and in the surrounding soil, together with improved bee husbandry and changes to honey handling procedures. 5 6 Life cycle is completed in the soil. Larvae Adults can locate colonies long distance, mature in 10-14 days and measure 10-11mm lay masses of eggs two - thirds the size of bee when fully grown. They crawl out of the hive at eggs in hive crevices and on combs. Eggs night to pupate in the soil. Adult beetles hatch hatch 2-6 days later. Laying adult females often out on average 3-4 weeks later. They measure lay masses of eggs at the same time 5-7mm (one - third the size of a worker bee) and are dark reddish brown to black 1 Larvae often clump together in combs cells and in the corners of frames The life cycle of the 2 small hive beetle (Aethina tumida) 3 Feeding activities of the larvae Larvae and adults preferentially causes fermentation and spoilage of honey. consume bee eggs and brood, Severe damage can occur in honey houses. as well as honey and pollen. It has a slimy appearance and smells of Tens of thousands of larvae ‘rotten oranges’ can be produced in each hive. 6 3 Close up of ‘Maggot-like’ SHB larva: There can be up to 30 larvae Note spines on the dorsum and 3 per cell.

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